1. Field of the Invention
The present invention relates to a method of efficiently managing dynamic multicast groups, and more particularly, to a method of efficiently managing dynamic multicast groups, which is capable of providing efficient group management, such as the extension or reduction of groups, through a hierarchical structure when multicast service is provided to a specific group in network environment.
2. Background of the Related Art
Multicast schemes have recently been applied to transmit digital information over a public network, such as paid TV, paid video service, and secret teleconference based on the Internet. In multicast communication, a group message is transmitted to all members belonging to a group. In general, in order to control access rights to information in a multicast group, data is encrypted using a group key (a session key). The group key is known to only the members within the group, and only member who know the key can decrypt messages. Multicast communication is excellent in terms of efficiency because messages are transmitted to each of n group members n times, but the messages have only to be sent to all members only once. The multicast communication however requires improvement in the stability of privacy resulting from a change in groups and the efficiency of a key update task because of the addition or deletion of members.
In the prior art, in the case where a new member joins a group or the existing member secedes from a group, problems arise in normal service and in the extension of groups because a group key update has to be frequently performed so as to update a group key and a session key used by members.